An electrochemical flow cell, also called a redox flow battery, is an electrochemical energy storage device, which is primarily classified into full vanadium flow and cell zinc-bromine, as well as is one kind of high-performance storage battery provided with separated positive and negative electrode electrolytes circulated individually, featuring high capacity, wide application field, long service life, flexible element design and etc.
As disclosed in U.S. published patent application no. 20120045680, entitled “Redox flow battery”, there is disclosed a redox flow battery comprising a battery tank, a membrane within the battery tank, and a positive electrode and a negative electrode respectively provided on two sides of the membrane. A positive electrode electrolyte and a negative electrode electrolyte are supplied to the battery tank. In this case, the positive electrode electrolyte contains a manganese ion. The negative electrode electrolyte contains at least one type of metal ion selected from a titanium ion, a vanadium ion, a chromium ion, a zinc ion, and a tin ion. The means of suppressing generation of a precipitation of MnO2 is obtained by further containing a titanium ion in the positive electrode electrolyte.
Generally speaking, the electrode is formed of modified carbon felt. In the carbon felt, however, high electric conductivity is provided in a horizontal direction, while low electric conductivity and small specific surface area, resulting in poor capacity of redox and thus reduced discharge power are provided in a vertical direction. Therefore, how to increase electric conductivity and specific surface area of the electrode in the vertical direction is truly a significant topic.